Article in Sierra on uses of poop (http://www.sierraclub.org/sierra/201201/grapple3.aspx):

Recap of article:

Uses of Poop:

1. Since pandas and elephants get the bulk of their nutrients from woody plants, their excrement could provide the key to cheap and effective biofuel.

2. Putrefying ponds of hog excrement are one of the nation's fastest-growing sources of methane, which can be used to generate electricity (a 9000 hog farm = energy for 35 homes)

3. Dried flakes of human waste fuel Thames Water, Britain's largest water and sewage company.